A Bright Idea: Fibre optic technology drives new methods of power measurement
Fibre optics have been at the heart of many remarkable discoveries into the industrial world. But none of these advances in fibre optic technology has had more potential than the measurement of power in mainline and commercial substations.
On first look, that might not appear very exciting. But this technical breakthrough could eliminate the presently-used, ceramic insulated, iron-core transformers — devices that degrade over time and sometimes fail catastrophically.
Utility deregulation sparks need for new technology
The need for safe and accurate measurement of current and voltage is not simply fuelled by replacement of failed conventional devices. It is driven by the trend towards power utility deregulation. The separation of generation, transmission and distribution, especially in the United States, is creating a burgeoning market for advanced technology. Like the long-distance telephone competition of the past decade, the drive to become "your power company" could soon become another commercial bazaar.
One company, NxtPhase, a Vancouver start-up technology firm, hopes to lead the power measurement race, an estimated $600 million market annually over the next decade. Started as a research project in 1993 at the University of British Columbia, NxtPhase was formed in 1999 as a combination of Carmanah Engineering and a group from Honeywell Inc., of Phoenix, Arizona. The company’s backers are convinced that their patented optical current and voltage transducers will become an essential link for sorting out the new energy marketplace.
The market for replacement of conventional power measurement devices, according to Steve Dolling, NxtPhase’s director of marketing, is about one percent per year. While this is a large and stable market, a further bonus lies in progressive deregulation.
Most power in Canada is now supplied by government subsidiary utilities. But in the U.S., large investor-owned firms are the norm, operating on fixed rates of return. In both cases, these suppliers monopolize supply, transmission and distribution. In many jurisdictions, they are being ordered to dismantle, and to sell off their generation and sometimes their distribution functions, to allow wider access to these functions and create a more efficient industry.
A network of firms — and power brokers — will result, with power sales and purchases at each interface. Under load fluctuations, some wholesale power costs can vary widely, often bearing no relationship to the selling price. For energy producers, base loads might be provided by steady-state sources such as nuclear or coal-fired plants. Peak power requirements will attract existing hydroelectric generators or independent natural gas-fired turbines which can be run efficiently during short peak demand periods. Each of these suppliers will require accurate power measurement.
"Power used to be measured only at the point of consumption," says Dolling. "Now, it will be measured at several interfaces. Power is changing hands. Some just buy and sell and don’t ever touch it."
Commercial users adapt to changing energy marketplace
There are, however, more than just the institutional players. Once power purchasing cost is subdivided into its components, it can vary by the hour, even by the minute. Factories and commercial users will find it economical to adjust their processes and the resulting power consumption, buying power when the price is most advantageous.
At the University of British Columbia (UBC), Professor Nick Jeager had invented a new technology based on the "Pockels" principle dating back 100 years. [see sidebar] Jeager and Farnoosh Rahmatian, who today is NxtPhase’s research and development director, developed the Integrated Optic Pockels Cell (IOPC) and a prototype for voltage measurement.
Carmanah Engineering, with the help of B.C. Hydro and UBC, has been testing this prototype since 1997 at the Ingledow Substation near Vancouver. But power measurement demands the assessment of current — as well as voltage — for this capability, so Carmanah went looking for a partner. Honeywell Inc.’s facility in Phoenix, Arizona, had perfected fibre optical technology for gyro devices, navigation equipment requiring extreme accuracy.
With researchers at Texas A & M University, they adapted the technology into a sensor for electrical current measurement. Both Honeywell and Carmanah realized the potential of their separate research projects. NxtPhase is the result of their cooperation, a combination of Carmanah Engineering with a spinout group from Honeywell’s Space and Aviation Controls Division, the American giant taking a 20 percent financial interest and extending a broad technical sharing agreement. At the same time, November 1999, the firm arranged another $9.1 million private equity placement from a consortium.
Two of Hydro-Quebec’s investment arms are participating, along with the Canadian Science and Technology Growth Fund, Western Technology Seed Investment Fund and the Working Opportunity Fund of British Columbia.
Richard MacKellar, former Carmanah President and now CEO of NxtPhase, is pleased with the collaboration. "The union creates an unparalleled technical group, well financed and ready to change the utility landscape," he says. With the Honeywell package comes a portfolio of more than 30 patents and a team of top researchers.
NxtPhase will maintain a facility in Phoenix, but 20 of the present staff of 30 live in Vancouver. The team is highly qualified, with a plethora of PhD’s in electrical engineering and optics. Steve Dolling says they will be building the first units for commercial sales by September of 2000. The current sensors will be built in Phoenix, but voltage sensors and column assemblies will be manufactured in Vancouver.
The products they are selling come from both ends of the consortium. The Optical Current Transducer (NXCT) is a lightweight device providing high accuracy over a wide dynamic range (of amperes.) The Optical Voltage Transducer (NXVT) measures the other side of the power equation. Used for both revenue metering and control, it has many advantages over conventional technology. Now, they have combined the two into a column that measures both current and voltage, designated NXVCT. The firm has a 230 kV prototype NXVCT under field test conditions at B.C. Hydro’s Ingledow Substation. In this three phase environment, there are three columns connected by fibre cable to an electronic package in the control building. Actually, these sensors have already been tested for three years in the Cholla generation station in Arizona. So the company is ready to start manufacturing for commercial markets.
The devices have several advantages over conventional measurement technologies. Weight and size improvements are clear, as are accuracy and safety considerations. But other firms also are producing non conventional devices. "We are not alone in this field," says Steve Dolling. One competitor uses a bulk optic technology for current sensing; in which an accurately machined and expensive crystal surrounds the conductor. Another uses a split magnetic core with a sensing element in the split.
Both approaches are limited, say NxtPhase officials, especially in measuring small currents, important to many independent power producers. The NXCT fibre optic current sensor uses a two-way loop, with as many (or as few) turns as needed. For voltage, others use the Pockel’s effect too, but with a large crystal between the line voltage and ground and dielectric gas (SF6) or fluid needed for large electrical stresses. The NXVT contains multiple electric field sensors, widely spaced between line voltage and ground to minimize electrical stress within the columns. And NxtPhase can combine both current and voltage measurement within one column. Right now, Alshom and ABB (both European-based firms) are servicing the new market.
The boom in electrical service of the 1960s is starting to repeat; the lifetime of much of that earlier equipment is 30-40 years and in the last couple of years the demand has picked up. Considering our reliance on electricity, companies like NxtPhase look to have a bright future. But so far, their products are directed to a limited number of known clients — the utilities and commercial users of power — not a large consumer market like automobile buyers.
The benefits of fibre-optic advances in the new energy marketplace
What do these new products mean to commercial users, the factories and managers responsible for energy? Depending upon the region, deregulation is coming sooner or later and power costs will be negotiable and flexible compared with today’s system. There will be a greater opportunity to organize plant functions to take advantage of cost breaks on power-greater incentive to do so.
The new optical sensors and their digital monitoring capability will also be able to cover a broad range of current and voltage, therefore useful for metering and for protection of equipment. Predictive maintenance can be identified earlier for cost and safety reasons. In special configurations, leakage currents in underground cables can be pinpointed. The transducers themselves will be safer and replacement costs lower.
Good power management can take advantage of some of these options even now. As deregulation visits more and broader regions, power generation and distribution options will multiply. Corresponding supply alternatives and cost options should benefit commercial users.
Gil Parker is a freelance writer who lives in Victoria, B.C. You can reach him at email@example.com.